A technical embodiment of a low-temperature carbonization of residues containing hydrocarbons is described in "Die Katalytische Druckhydrierung von Kohlen, Teeren und Mineraloelen" (The Catalytic Hydrogenation Under Pressure of Coals, Tars, and Crude Oils) Springer-Verlag, Berlin/Goettingen/Heidelberg, 1950. According to that treatise, the liquid residue containing hydrocarbons and heated to about 400.degree. C. to 450.degree. C. is sprayed into the low-temperature carbonization chamber, which is heated by external gas heating to about 550.degree. C. to 600.degree. C. A distillation to coke occurs, and the distilling off of the recoverable hydrocarbon oil portion can be promoted by countercurrent addition of about 10% of superheated steam. The low-temperature residue is removed by water immersion at the end of the furnace opposite the intake (see page 45). Thus, such devices that were placed on the discharge side inclined slightly downwardly from the horizontal were often provided as so-called ball furnaces with a feed of steel balls to cause, by flat ribs welded on as drivers in the lengthwise direction, the balls in the rotating furnace to be driven as high as possible so that, when falling, they knocked the forming encrustations loose (see page 254).
In addition to the working up of residues containing hydrocarbons coming from coal or crude oil, waste substances such as synthetic wastes, residues laden with hydrocarbons, contaminated soil, biomasses, sludges, and the like can be worked up by low-temperature carbonization into liquid product and low-temperature tar in addition to low-temperature gas and low-temperature coke.
Therefore, it has been proposed to subject household, industrial, and commercial garbage and special waste substances to a low temperature pyrolysis in a suitable reactor (e.g., a rotary kiln). See, e.g., DE-PS 29 47 293 and EP-0 111 081 Al.
Comparatively few publications discuss the equipment side of such processes, especially the making available of improved rotating cylinder designs. A satisfactory sealing of the rotating parts of a rotating cylinder from the stationary parts that receive the product feed or product discharge pipes is still a technical problem the solution of which causes considerable difficulties because of the prevailing mechanical and thermal stresses.
Therefore, according to DE 33 46 338 Al there has been proposed a sealing arrangement with a slide ring sealing system and a sealing disk placed on a rotating part of a rotating cylinder as well as sealing, adjacent thrust rings.
Significant drawbacks of the standard-built rotating cylinder designs known in the prior art are the heat losses in the area of the bearing races built directly into the rotating cylinder, the problems that have occurred in sealing between the stationary rotating cylinder heads and the rotating cylinder, and the problems associated with the thermal expansion of the rotating cylinder.
The heat losses associated with the bearing races and also with the drive of the rotating cylinder, which is often performed as a chain drive by gearwheels, also lead to a decrease in the liquid product yield because of premature condensation with subsequent cracking and polymerization reactions. The known rotating cylinder designs are usually designed with a soft, axial expansion compensator for the rotating cylinder head. The sealing function of the sealing part (for example, rotating with pressure rollers pressed on the stationary sealing part and containing two sealing packings) is considerably impaired by rotating cylinder eccentricities.